Widespread fog has developed across the region given abundant low- level moisture and light winds. Surface observations and webcams show visibility dropping as low as 1/4 mile, mainly in areas east of the James River. Hi- res models and sref prob model suggest fog will continue to expand east-southeast into far eastern counties in southeast South Dakota, northwest Iowa and southwest Minnesota through early morning. Have issued a dense fog advisory through 9 am CDT.

Ridge aloft builds over the Central Plains as an upper-level wave moves into the Pacific northwest. This pattern will result in another quiet but warmer and humid day. Highs will generally range in the 80s. Low-level moisture and continued southerly winds will keep mild temperatures tonight with lows from the mid 60s to near 70.

The workweek starts off with well-above normal temperatures as the upper level ridge axis/southwest flow aloft dominates the region. This will result in even warmer weather compared to Sunday. 850 hpa temperatures suggest values in the 20 to 23c range; therefore high temperatures could reach the upper 80s to near 90s. Will continue to monitor these temperatures as it will also depend on the amount of cloud cover across the area.

A weak shortwave ejects northeast from The Rockies on Monday, reaching the region Monday night into Tuesday. This could result in some thunderstorms as the low level jet strengthens.

Tuesday looks to feature another warm day, with highs ranging from the mid to upper 80s. Weather pattern changes later on Tuesday as a negatively tilted upper wave pivots inland over The Rockies. Ahead of this main upper wave, a mid-upper level trough moves over the High Plains later on Tuesday. Models are in better agreement with this shortwave and bring most of the precipitation late Tuesday night into early Wednesday. However, confidence in specific details remains low.

The next chance for precipitation, and possibly more impacts across our region, arrives towards the end of the week as the aforementioned upper wave moves through the plains.

Areas of dense fog will continue through mid morning, impacting mainly khon and kfsd. Low level wind shear could impact khon late this evening into the overnight hours. Otherwise, VFR conditions are expected after mid-morning at all sites.